Conductive-wire position inspecting method and device

ABSTRACT

A conductive-wire position inspecting device includes: a reference body disposed in a radial direction of a stator core; an imaging device configured to image a conductive wire and the reference body; and a calculating device configured to find a relative position and a relative angle of the conductive wire with respect to the reference body, based on an obtained image. In addition, the conductive-wire position inspecting device includes a determining device configured to determine whether or not the found relative position and relative angle are within respective permissible ranges, and if they are within the permissible ranges, determine the position of the conductive wire to be acceptable.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of application Ser. No. 16/243,178filed on Jan. 9, 2019, the entire contents of which are incorporatedherein by reference.

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2018-004717 filed on Jan. 16, 2018, thecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a conductive-wire position inspectingmethod for inspecting whether or not a position of a conductive wireinserted in a slot of a stator core is within a reference range, andalso to a conductive-wire position inspecting device.

Description of the Related Art

There is known a stator in which two of a plurality of slots formedalong a circumferential direction of a circular ring shaped stator corehave inserted therein a segment-for-coil (hereafter, also expressedsimply as a “segment”) which is a conductive wire. Now, the segment issubstantially U-shaped, having a first leg, a second leg that extendssubstantially in parallel to the first leg, and a turn section thatbends so as to connect the first leg with the second leg. The pluralityof slots are formed radially, so when the first leg and the second legare inserted in the slot in order to manufacture the stator, forexample, the first leg faces an inner circumferential side of the statorcore, and the second leg faces an outer circumferential side of thestator core.

It is required that positions of tips of the first leg and the secondleg projecting from the slot are within a certain reference value withrespect to the circumferential direction and a radial direction of thestator core. This is because if a positional deviation falls outside thereference value, then when the segment is twisted to be joined toanother leg, a strength of that joining will be insufficient.

Accordingly, after the first leg and the second leg have been insertedinto the slot, an inspection of tip positions of the first leg and thesecond leg is performed. For example, Japanese Laid-Open PatentPublication No. 2014-135819 describes an inspection method thatphotographs a tip surface of a leg by an imaging device and finds aposition of an intersection point of diagonal lines within the tipsurface, and finds by calculation an amount of deviation between theintersection point position and a regular position.

SUMMARY OF THE INVENTION

The inspection method described in Japanese Laid-Open Patent PublicationNo. 2014-135819 is configured so as to find the intersection point atwhich the diagonal lines intersect by artificially assuming to bequadrangular the tip surface which originally is not quadrangular.Therefore, a complicated calculation must be performed. Moreover, sincea calculation is performed for the tip surfaces of the individual legs,a long time is required until calculation on all of the legs finishes.That is, a defect of inspection efficiency being poor, is apparent.

A main object of the present invention is to provide a conductive-wireposition inspecting method that enables a time from start to finish tobe reduced.

Another object of the present invention is to provide a conductive-wireposition inspecting device by which efficiency of the conductive-wireposition inspecting method can be improved.

According to an aspect of the present invention, there is provided aconductive-wire position inspecting method for inspecting a position ofa conductive wire inserted into a slot of a stator core, the methodincluding:

a disposing step of disposing a reference body so that the referencebody and the conductive wire projecting from the slot are arranged alonga line in a radial direction of the stator core;

an imaging step of imaging the conductive wire and the reference bodywith an imaging device;

a calculating step of finding a relative position and a relative angleof the conductive wire with respect to the reference body, with acalculating device, based on an image obtained by the imaging device;and

a determining step of, if the relative position and the relative anglefound in the calculating step are within respective permissible ranges,determining the position of the conductive wire to be acceptable, with adetermining device.

Moreover, according to another aspect of the present invention, there isprovided a conductive-wire position inspecting device for inspecting aposition of a conductive wire inserted into a slot of a stator core, thedevice including:

a reference body disposed so that the reference body and the conductivewire projecting from the slot are arranged along a line in a radialdirection of the stator core;

an imaging device configured to image the conductive wire and thereference body;

a calculating device configured to find a relative position and arelative angle of the conductive wire with respect to the referencebody, based on an image obtained by the imaging device;

and a determining device configured to, if the relative position and therelative angle found by the calculating device are within respectivepermissible ranges, determine the position of the conductive wire to beacceptable.

Thus, the present invention is configured such that the reference bodyserving as a reference of position is provided separately from theconductive wire, and the relative position and the relative angle of theconductive wire with respect to this reference body are found. That is,a deviation amount of the conductive wire with respect to the referencebody is obtained by calculation, and it is determined whether or notthis deviation amount is within the permissible range (the referencerange). Therefore, there is no need for a calculation to be performedfor each of the tip surfaces of the legs. In other words, calculationbecomes simple. Accordingly, a reduction in time required forcalculation may be achieved, and an improvement in inspection efficiencycan be achieved.

In the calculating step, for example, a reference line extending alongthe radial direction of the stator core may be drawn from the referencebody, and the relative position and the relative angle of the conductivewire with respect to this reference line may be found. Employing thereference line makes calculation even simpler.

It is preferable that when a plurality of the conductive wires arearranged along the radial direction of the stator core, a relativeposition and a relative angle of each of the plurality of conductivewires with respect to the reference body are found in the calculatingstep. As a result, it can be determined collectively whether or not therelative position and the relative angle are within the respectivepermissible ranges (the reference ranges) for the plurality ofconductive wires. Therefore, inspection efficiency can be improved evenmore.

In some case, a plurality of the conductive wires are arranged along thecircumferential direction of the stator core. In this case, after theposition of one inspection target conductive wire is determined to beacceptable in the determining step, another conductive wire that isadjacent to the one conductive wire in the circumferential directionundergoes the imaging step, the calculating step, and the determiningstep. This makes it possible for an inspection to be performed on all ofthe conductive wires inserted in the slots of the stator core.

In order to configure such that the imaging step, the calculating step,and the determining step are sequentially performed on the conductivewires adjacent in the circumferential direction, a rotating deviceconfigured to rotate the stator core relatively to the imaging devicemay be provided. Note that the imaging device may be positioned andfixed, and the stator core may be rotated. Alternatively, the statorcore may be positioned and fixed, and the imaging device may be rotated.

In all cases, the reference body is preferably positioned and fixed. Inthis case, it is avoided that the reference body undergoes a positionaldisplacement with respect to the stator core. In other words, a relativeposition of the reference body with respect to the stator core is fixed.

In the case where the calculation is performed using the reference line,the reference line may be given by calculation with the calculatingdevice. Alternatively, it is also possible for the reference line to beprovided in the imaging device or a member interposed between theimaging device and the reference body. In this case, calculation forgiving the reference line becomes unnecessary, so calculation becomeseven simpler.

Due to the present invention, a configuration is adopted whereby areference body serving as a reference of position is provided, arelative position and a relative angle of a conductive wire with respectto this reference body are found, and it is determined whether or notthe relative position and the relative angle are within respectivepermissible ranges (a reference range). Because the reference body isused as a reference, there is no need for a calculation to be performedfor each of the tip surfaces of the legs, and, proportionately,calculation becomes simple.

Therefore, a reduction in time required for calculation, andconsequently, a reduction in time required from start to finish ofinspection, can be achieved. As a result, an improvement in inspectionefficiency can also be achieved.

The above and other objects, features, and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings, in which apreferred embodiment of the present invention is shown by way ofillustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic overall perspective view of a conductive wire (asegment) configuring an electromagnetic coil of a stator;

FIG. 2 is a schematic plan view showing both a stator core with thesegments of FIG. 1 being inserted into slots thereof, and main parts ofa conductive-wire position inspecting device according to an embodimentof the present invention;

FIG. 3 is an enlarged schematic plan view of main parts showing a methodof calculation of a relative position and a relative angle of thesegment with respect to a reference body; and

FIG. 4 is an enlarged schematic plan view of main parts showing a methodof correction when a perpendicular side cannot be found in an image ofthe reference body.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of a conductive-wire position inspecting methodin relation to a conductive-wire position inspecting device forimplementing the method according to the present invention, will bepresented and described in detail below with reference to theaccompanying drawings.

First, a segment 10 (a conductive wire) shown in FIG. 1 and a statorcore 20 shown in FIG. 2, will be described. FIG. 1 is a schematicoverall perspective view of the segment 10 to be inserted into a slot 22of the stator core 20 (refer to FIG. 2). The segment 10 includes: twolegs 12, 12 extending substantially in parallel to each other; and aturn section 16 interposed between the two legs 12, 12. Due to the turnsection 16 bending from one leg 12 toward the other leg 12, the segment10 is substantially U-shaped.

A crank section 18 of meandering shape is formed in the turn section 16.Due to this crank section 18, a displacement occurs in a direction alonga radial direction of the stator core 20, in the segment 10.

The segment 10 having the above shape has one of its legs 12 insertedinto one of a plurality of the slots 22 provided in the stator core 20in FIG. 2, and has its other leg 12 inserted into another one of theslots 22. As a result, the segment 10 becomes an electrical path betweenthe two slots 22. That is, an electrical continuity-enabled state isattained between the slot 22 into which the one leg 12 has been insertedand a different slot 22 into which the other leg 12 has been inserted.

Meanwhile, the stator core 20 is configured as a laminated body having aplurality of core plates laminated therein. Each of the core platesincludes: a circular ring section 24; and tab sections 26 projectingfrom an outer periphery of the circular ring section 24. The slots 22are formed so as to circle along an inner circumference of the circularring section 24. Note that a longitudinal direction of the slot 22 is adiametrical direction of the circular ring section 24, hence the slot 22extends radially.

In addition, each of the tab sections 26 has a fastening hole 28 formedin substantially a center thereof. By an unillustrated bolt passedthrough this fastening hole 28 being screwed into an unillustrated bolthole formed in a rotating table 40 (described later) shown in FIG. 2,the laminated core plates are secured and the stator core 20 ispositioned and fixed to the rotating table 40.

Next, main parts of a conductive-wire position inspecting deviceaccording to the present embodiment will be described with reference toFIG. 2. This conductive-wire position inspecting device includes: therotating table 40 (a rotating device) on which the stator core 20 isplaced; a reference block 42 (a reference body) arranged above thestator core 20 and positioned on an inner circumferential side of thestator core 20 in planar view; a camera 44 as an imaging device; and acomputer 46.

The rotating table 40 is rotatable about a point O, under action of arotary drive motor 100. The stator core 20 with the legs 12 of thesegment 10 inserted in the slots 22 is placed on this rotating table 40,and the stator core 20 is subsequently positioned and fixed as describedabove. Note that the stator core 20 is set in a posture that the legs 12of the segment 10 face upwardly and the turn section 16 facesdownwardly. Moreover, the segment 10 is already twisted.

In this case, the reference block 42 includes a block main body 50 andfirst through third reference claw sections 52 a to 52 c. Of these, theblock main body 50 is substantially a square body. A supporting shaft 54attached to an unillustrated supporting body is coupled to the center ofthe block main body. Therefore, the reference block 42 is supported bythe supporting body via the supporting shaft 54.

The first through third reference claw sections 52 a to 52 c are formedprojecting toward an outer side in the radial direction of the statorcore 20 from an outer edge section of the block main body 50. That is,an angle made by the adjacent reference claw sections 52 a, 52 b (or 52b, 52 c) matches an angle made by the adjacent slots 22.

The camera 44 is disposed above the stator core 20 and photographs suchthat upper surfaces of the first through third reference claw sections52 a to 52 c and a tip surface of the leg 12 will be within the sameimage. An image obtained by photographing is sent to the computer 46 viaa signal line 55 a. Moreover, there is arranged in a vicinity of thecamera 44 a laser beam irradiation apparatus 56 for irradiating avicinity of a photographing range with a laser beam.

The computer 46 serves both as a calculating device and a determiningdevice. That is, the computer 46 calculates and thereby determineswhether or not the tip surface of the leg 12 is within a referencerange, based on the image photographed by the camera 44.

The rotary drive motor 100 has the computer 46 electrically connectedthereto via a signal line 55 b, and has the rotating table 40 coupled toits rotary drive shaft. The rotary drive shaft is index-rotated undercontrol action of the computer 46. Along with this index rotation, therotating table 40 index-rotates integrally with the rotary drive shaft.

The conductive-wire position inspecting device according to the presentembodiment is basically configured as above, and next, will bedescribed, concerning its operation and advantageous effects, inrelation to a conductive-wire position inspecting method according tothe present embodiment.

First, calibration is performed using a calibration master (i.e., areference element for calibration). That is, the calibration master isdisposed in the vicinity of the first through third reference clawsections 52 a to 52 c of the reference block 42, and the distance fromthe first through third reference claw sections 52 a to 52 c to thecalibration master is actually measured. In the meantime, theconductive-wire position inspecting device is used to obtain thedistance from the first through third reference claw sections 52 a to 52c to the calibration master in accordance with the later-mentionedconductive-wire position inspecting method.

Then, a difference between the actually measured distance and thedistance obtained by the conductive-wire position inspecting device iscalculated. All that is required is a configuration whereby thisdifference is added as a correction amount to the distance obtained bythe conductive-wire position inspecting method. This makes it possibleto determine even more accurately whether or not a tip position of theleg 12 of the segment 10 is within a certain reference value range.

Next, in order to implement a conductive-wire position inspection, thestator core 20 is placed on the rotating table 40, and fixedlypositioned thereon. At this time, as shown in FIG. 3, each of the threeslots 22 and the corresponding one of the first through third referenceclaw sections 52 a to 52 c are arranged along a line in the radialdirection. That is, a disposing step is implemented. Hereafter, in orderto facilitate distinction, the slot 22 that is aligned with the firstreference claw section 52 a in the radial direction will be referred toas a lower slot 22 a, the slot 22 that is aligned with the secondreference claw section 52 b in the radial direction will be referred toas a middle slot 22 b, and the slot 22 that is aligned with the thirdreference claw section 52 c in the radial direction will be referred toas an upper slot 22 c. The camera 44 adopts as its photographing rangethese first through third reference claw sections 52 a to 52 c and lowerthrough upper slots 22 a to 22 c.

The laser beam irradiation apparatus 56 irradiates the above-describedphotographing range with a laser beam. As a result, the photographingrange becomes brighter. Meanwhile, the camera 44 photographs (images)the brightly illuminated upper surfaces of the first through thirdreference claw sections 52 a to 52 c and tip surface of each of the legs12 within the lower through upper slots 22 a to 22 c. In this way, animaging step is performed.

Next, a calculating step is performed by the computer 46. That is, thecomputer 46 performs calculation to find first through third referencelines L1 to L3 that extend along the radial direction of the stator core20, from each of the first through third reference claw sections 52 a to52 c. Explaining this specifically exemplifying the first reference clawsection 52 a and the first reference line L1, the computer 46 firstdemarcates or determines a vertical side 60 extending substantially inparallel to a circumferential direction of the stator core 20, of thefirst reference claw section 52 a.

Next, the computer 46 determines a first horizontal side 62 a and asecond horizontal side 62 b that extend substantially in parallel to theradial direction of the stator core 20, of the first reference clawsection 52 a. As a result, an intersection point A of the vertical side60 and the first horizontal side 62 a and an intersection point B of thevertical side 60 and the second horizontal side 62 b, are found.

Next, the computer 46 draws a line segment passing through theintersection point A and the intersection point B. A perpendicularbisector of this line segment will be the first reference line L1. Thecomputer 46, substantially simultaneously to finding the first referenceline L1, finds the second reference line L2 and the third reference lineL3 similarly to as described above.

A position through which each of the thus found first through thirdreference lines L1 to L3 passes and a position of a center line of eachof the legs 12 (a diametrical line of the stator core 20 passing througha center point of each leg 12) within each of the lower through upperslots 22 a to 22 c, are compared. FIG. 3 shows a state where the secondreference line L2 and the center line of the legs 12 within the middleslot 22 b coincide, whereas the first reference line L1 and the thirdreference line L3 are positioned slightly more upwardly than centerlines M1 and M3 of some of the legs 12 within the lower slot 22 a andthe upper slot 22 c.

Next, in order to perform a determining step, the computer 46 furthercalculates whether or not a deviation amount X (a relative position)between the first reference line L1 and the center line of each of thelegs 12 within the lower slot 22 a is within a preset permissible range(a reference range), and whether or not a deviation amount Y (a relativeposition) between the third reference line L3 and the center line ofeach of the legs 12 within the upper slot 22 c is within the presetpermissible range (the reference range). Furthermore, the computer 46calculates and thereby finds an angle (a relative angle) made by thecenter line of each of the legs 12 and the corresponding one of thefirst through third reference lines L1 to L3.

Then, in order to perform the determining step, the computer 46determines whether or not the deviation amounts X, Y and the angles, inother words, the relative position and the relative angle of each of thelegs 12 with respect to the corresponding one of the first through thirdreference claw sections 52 a to 52 c, are within respective permissibleranges. If within the permissible ranges, the computer 46 determines(the positions of) the legs 12 to be “acceptable”, and integrallyindex-rotates the rotary drive shaft and the rotating table 40.

Due to this index-rotation, new three slots 22 become new lower throughupper slots 22 a to 22 c with respect to the first through thirdreference claw sections 52 a to 52 c. The legs 12 within these new lowerthrough upper slots 22 a to 22 c undergo a calculation and determinationsimilar to the above-described. This is repeated, and when (thepositions of) all of the legs 12 are determined to be acceptable, thestator core 20 is conveyed to a joining station where the legs 12 arejoined together. In contrast, the leg 12 that is determined to beunacceptable undergoes a re-disposing in order to set its deviationamount within the permissible range.

Thus, in the present embodiment, it can be simultaneously determinedwhether or not positions of the legs 12 within a plurality of the slots22 are within the reference range, merely by performing a simplecalculation. That is, a time required for position inspection of all ofthe legs 12 can be reduced in comparison with conventional technology.Therefore, efficiency of the position inspection rises.

Note that there may occur an image where corners of the first throughthird reference claw sections 52 a to 52 c are inclined due to the likesof diffused reflection or ghosting. Accordingly, a configuration may beadopted whereby when the computer 46 performs calculation, a portionexcluding the corners is extracted from the vertical side 60, as betweenC and D in FIG. 4. In this case, there should be a configuration wherebysubsequently, the extracted portion is divided into equal intervals andaveraged to find the vertical side 60.

Alternatively, a configuration may be adopted whereby a lens of thecamera 44 is provided beforehand with the first through third referencelines L1 to L3. In this case, the computer 46 only has to calculatedeviation amounts of the first through third reference lines L1 to L3and the center lines of the legs 12 within the lower through upper slots22 a to 22 c. Therefore, even more reduction of the time required forinspection or even further improvement of inspection efficiency can beachieved. There may also be a configuration whereby the first throughthird reference lines L1 to L3 are provided to a transparent body,instead of to the lens of the camera 44, and this transparent body isinterposed between the camera 44 and the reference block 42.

The present invention is not particularly limited to the above-describedembodiment, and a variety of changes are possible in a range notdeparting from the scope of the present invention.

For example, although the above-described embodiment is configured suchthat the stator core 20 is set in a posture that the legs 12 faceupwardly and the turn section 16 faces downwardly, and the referenceblock 42 and camera 44 are arranged above the legs 12, it may beconfigured oppositely to this. That is, it is also possible to adopt aposture where the legs 12 face downwardly and the turn section 16 facesupwardly, and the reference block 42 and camera 44 are arranged belowthe legs 12. In this case, a configuration may be adopted whereby therotating table 40 is provided with the likes of gripping claws that gripthe stator core 20.

In addition, a configuration may be adopted whereby the reference block42 is arranged on an outer circumferential side of the stator core 20.In this case, the reference line may be drawn toward the leg 12positioned on the outermost side within the slot 22.

Moreover, the number of reference claw sections provided in thereference block 42 is not particularly limited to three, and there maybe, for example, five or more. Furthermore, the number of reference clawsections may correspond to the number of slots 22. In the latter case, aconfiguration may be adopted whereby the camera 44 and the laser beamirradiation apparatus 56 are revolved along the circumferentialdirection of the stator core 20.

What is claimed is:
 1. A conductive-wire position inspecting method forinspecting positions of a plurality of conductive wires inserted into aslot of a stator core and arranged in a radial direction of the statorcore, the method comprising: a disposing step of disposing a referencebody so that the reference body and the conductive wires projecting fromthe slot are arranged along a line in the radial direction of the statorcore; an imaging step of imaging the conductive wires and the referencebody with an imaging device; a calculating step of finding a deviationamount of each of the conductive wires with respect to a reference linedrawn from the reference body and extended along the radial direction ofthe stator core, based on an image obtained by the imaging device; and adetermining step of, if the deviation amount found in the calculatingstep falls within a permissible range, determining the position of theconductive wire to be acceptable.
 2. The conductive-wire positioninspecting method according to claim 1, wherein the conductive wirescomprise a plurality of conductive wires that are arranged along acircumferential direction of the stator core, and after the position ofone of the conductive wires is determined to be acceptable in thedetermining step, another one of the conductive wires that is adjacentto the one conductive wire in the circumferential direction undergoesthe imaging step, the calculating step, and the determining step.
 3. Aconductive-wire position inspecting device for inspecting a position ofa plurality of conductive wires inserted into a slot of a stator coreand arranged in a radial direction of the stator core, the devicecomprising: a reference body disposed so that the reference body and theconductive wire projecting from the slot are arranged along a line inthe radial direction of the stator core; an imaging device configured toimage the conductive wires and the reference body; a calculating deviceconfigured to find a deviation amount of each of the conductive wireswith respect to a reference line drawn from the reference body andextended along the radial direction of the stator core, based on animage obtained by the imaging device; and a determining deviceconfigured to, if the deviation amount found by the calculating devicefalls within a permissible range, determine the position of theconductive wire to be acceptable.
 4. The conductive-wire positioninspecting device according to claim 3, further comprising a rotatingdevice configured to rotate the stator core relatively to the imagingdevice and the reference body.
 5. The conductive-wire positioninspecting device according to claim 3, wherein the imaging device andthe reference body is positioned and fixed.
 6. The conductive-wireposition inspecting device according to claim 3, wherein the referenceline is provided in the imaging device or a member interposed betweenthe imaging device and the reference body.